{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T04:56:18Z","timestamp":1790571378089,"version":"4.1.0"},"reference-count":48,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T00:00:00Z","timestamp":1790553600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Cell. Infect. Microbiol."],"abstract":"\n Background<\/jats:title>\n \n CTX-resistant Salmonella infections threaten public health. This study aimed to characterize the genetic environments of\n bla<\/jats:italic>\n CTX-M<\/jats:sub>\n \/\n bla<\/jats:italic>\n CMY-2<\/jats:sub>\n in CTX-resistant non-typhoidal\n Salmonella<\/jats:italic>\n from patients with diarrhea in Chongqing, China (2022\u20132024).\n <\/jats:p>\n <\/jats:sec>\n \n Methods<\/jats:title>\n \n Among 306\n Salmonella<\/jats:italic>\n isolates recovered from seven hospitals, 36 (11.8%) were confirmed as CTX-resistant. Antimicrobial susceptibility testing, whole-genome sequencing (WGS), genetic structure analysis, conjugation experiments, and core-genome single nucleotide polymorphism (cgSNP) analysis were performed.\n <\/jats:p>\n <\/jats:sec>\n \n Results<\/jats:title>\n \n All 36 CTX-resistant isolates were resistant to CTX and ampicillin; resistance rates to chloramphenicol (88.9%), tetracycline (86.1%), and ceftazidime (63.9%) were high. Thirteen serotypes were identified, with\n S<\/jats:italic>\n . I 4,[5],12:i:- (30.6%),\n S.<\/jats:italic>\n Goldcoast (16.7%), and\n S.<\/jats:italic>\n Typhimurium (11.1%) being the most frequently identified. The most frequently detected ESBL genes were\n bla<\/jats:italic>\n CTX-M-65<\/jats:sub>\n (17\/36) and\n bla<\/jats:italic>\n CTX-M-55<\/jats:sub>\n (11\/36).\n bla<\/jats:italic>\n CMY-2<\/jats:sub>\n occurred in five isolates.\n QnrS<\/jats:italic>\n co-carriage was 72.2% (26\/36). IS\n Ecp1<\/jats:italic>\n flanked\n bla<\/jats:italic>\n CTX-M<\/jats:sub>\n \/\n bla<\/jats:italic>\n CMY-2<\/jats:sub>\n in 94.4% (34\/36) of isolates, highlighting its major role in mobilizing these resistance genes. IncHI2A was the most frequently identified plasmid (50.0%). In an\n S<\/jats:italic>\n . I 4,[5],12:i:- isolate, a 96,117-bp IncI1 plasmid carrying IS\n Ecp1<\/jats:italic>\n -\n bla<\/jats:italic>\n CMY-2<\/jats:sub>\n was 100% identical to a Botswana\n E. coli<\/jats:italic>\n plasmid. In an\n S<\/jats:italic>\n . Thompson isolate, a 152,834-bp IncC plasmid carrying the same transposition unit shared &gt;99% identity with a plasmid from a Hefei clinical isolate. Notably, a novel 75,302-bp IS\n Ecp1<\/jats:italic>\n -mediated transposition unit carrying\n bla<\/jats:italic>\n CTX-M-65<\/jats:sub>\n , together with the entire IncI plasmid backbone, was identified with 5-bp direct repeats. This unit is far larger than typical IS\n Ecp1<\/jats:italic>\n -mediated insertions (2.9\u20133.0 kb).\n <\/jats:p>\n <\/jats:sec>\n \n Conclusion<\/jats:title>\n \n Our findings suggest that ISEcp1 is associated with the dissemination of\n bla<\/jats:italic>\n CTX-M<\/jats:sub>\n \/\n bla<\/jats:italic>\n CMY-2<\/jats:sub>\n among CTX-resistant isolates in this regional collection, and suggest the potential to mobilize large DNA segments. Enhanced genomic surveillance of such mobile elements is urgently needed in this region.\n <\/jats:p>\n <\/jats:sec>","DOI":"10.3389\/fcimb.2026.1891482","type":"journal-article","created":{"date-parts":[[2026,9,28]],"date-time":"2026-09-28T04:29:16Z","timestamp":1790569756000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["ISEcp1-associated dissemination of blaCTX-M\/blaCMY-2 among cefotaxime-resistant non-typhoidal Salmonella from patients with diarrhea in Chongqing, China, 2022\u20132024"],"prefix":"10.3389","volume":"16","author":[{"given":"Na","family":"Zhao","sequence":"first","affiliation":[{"name":"Chongqing Wanzhou Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Gang","family":"Duan","sequence":"additional","affiliation":[{"name":"Chongqing Municipal Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu","family":"Liu","sequence":"additional","affiliation":[{"name":"Chongqing Wanzhou Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Chunyan","family":"Liao","sequence":"additional","affiliation":[{"name":"Chongqing Municipal Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ling","family":"Wang","sequence":"additional","affiliation":[{"name":"Chongqing Municipal Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yu","family":"Zhao","sequence":"additional","affiliation":[{"name":"Chongqing Wanzhou Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yanbin","family":"Zhou","sequence":"additional","affiliation":[{"name":"Yuzhong District Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Fei","family":"Chen","sequence":"additional","affiliation":[{"name":"Chongqing Shapingba Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Caiyun","family":"Li","sequence":"additional","affiliation":[{"name":"Chongqing Nanan Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Tingyan","family":"Sun","sequence":"additional","affiliation":[{"name":"Chongqing Yongchuan Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yong","family":"Zhu","sequence":"additional","affiliation":[{"name":"Chongqing Rongchang Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Mansha","family":"Yuan","sequence":"additional","affiliation":[{"name":"Chongqing Wanzhou Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Linghan","family":"Kong","sequence":"additional","affiliation":[{"name":"Chongqing Wanzhou Center for Disease Control and Prevention","place":["Chongqing, China"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2026,9,28]]},"reference":[{"key":"B1","doi-asserted-by":"publisher","first-page":"455","DOI":"10.1089\/cmb.2012.0021","article-title":"SPAdes: a new genome assembly algorithm and its applications to single-cell sequencing","volume":"19","author":"Bankevich","year":"2012","journal-title":"J. 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